Accurate, localized quantification of white matter perfusion with single-voxel ASL.

Quantification of perfusion in white matter is still difficult due to its low level, causing an often insufficiently low signal-to-noise ratio, and its long and inhomogeneous transit delays. Here, a technique is presented that accurately measures white matter perfusion by combining a spectroscopic single-voxel localization technique (point-resolved spectroscopy) with a pulsed arterial spin labeling encoding scheme (flow-sensitive alternating inversion recovery) to specifically address the properties of white matter. The transit delay was measured by shifting the position of a slice-selective saturation pulse between inversion and acquisition. Perfusion measurements resulted in values of 15.6 ± 3.2 mL/100 g/min in the left and 15.2 ± 4.8 mL/100 g/min in the right hemispheric white matter and 83.2 ± 15.2 mL/100 g/min in cortical gray matter. Taking dispersion of the transit times into account does not cause a significant change in the measured values.